Switch lock for power-driven tools



March 11, 1952 R. B. PEALER SWITCH LOCK FOR POWER-DRIVEN TOOLS 2 Sl-IEETSSHEET 1 Filed NOV. 15, 1948 mwmw A ,liv

March 11, 1952 R. B. PEALER SWITCH LOCK FOR POWER-DRIVEN TOOLS 2 SHEETSSHEET 2 Filed NOV. 15, 1948 I INVENTOR.

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Patented Mar. 11, 1952 SWITCH LOCK FOR POWER-DRIVEN TOOLS Robert B. Pea'ler, Garrettsville, Ohio, assignor to Beaver Pipe Tools, Inc., Warren, Ohio, a cor- 'p'oration of "Ohio Application November 13, 1948, Serial No. 59,795

11 Claims.

This invention relates to a safety lock for "the controlling switch of an electrically driven power tool. Many power driven machine tools, as for example pipe working machines, have rotary chucks the jaws of which must be "set in clamping position by a removable manual wrench. Such Wrench when in use usually project's radially from the chuck head. It sometimes happens that the operator forgets to remove the chuck Wrench "after effecting the clamping and "starts the machine With the wrench Still "in the Chuck head. The result is that the projecting wrench is carried around by the rotary "chuck "head and may cause injury to the "operator or may "come into engagement with the bed of the machine or some other fixed part and cause "breakage of some part of the "machine.

The object of this invention is to'providemeans to prevent the starting of the machine in case the operator inadvertently leaves the chuck wrench standing in the chuck. To this end, I have provided a holding device which normally locks the switch in neutral position and has provision for "supporting the chuck wrench. When the chuck wrench is put on such'sup'portit acts to release the lock from the switch lever, 'allowing the operator to 'move the switch in the "usual manner.

The "present invention, "as illustrated in the accompanying drawings and hereinafter fully described, is concerned especially with power machines'having an electric switch the control lever of which moves in a "horizontal plane, as forinstance the well-known type of barrel switch .h'aving the operating lever projecting horizontally from the top of the vertical housing containing the barrel and contact fingers. "Such lever is usually swung 'from a central "off" position in either direction "for forward or reverse rotation "of the'motor control thereby. Simplicity, cheapness or construction .of the switch locking device, as well as its adaptability for mounting on the existing tools having such switches, are features of the present invention.

'In the drawings, Fig. 1 is aside elevation of a machine tool in the "form of a power drive for holding "and "rotating the pipe to be cut or threaded, this 1 machine tool "having fa barrel switch, the 'operatingle'ver of which is shown as locked by my locking device; 'Fig. '2 is an end view on a larger scale of the "machine shown in Fig. 1, looking from the left hand end; .Fig. 3

is a "perspective of a barrel switch on v.aportion of 'aim'a'chine tool, showing my device in looking position, 'due'to theabsence'o'f'the chuck wrench.

Fig. 4 is a similar view showin the locking de vice in unlocking position with the chuck Wrench present; Fig. 5 is a .plan of the barrel switch with the locking device retained .in locking position by its spring, the chuck wrench being ansent; Fig. 6 is a fragmentary vertical section of the forward portion of the locking device held in released position by the chuck wrench.

.InFigs. 1 and 2, H] indicates any suitable bed from which rises a hollow housing I having laterally extending hollow bearing portions l2 and I3. Mounted in hearings in these extensions is a rotary barrel [4 carrying .a chuck head 15. The laws iii of this chuck are controlled by a radial socket I1 suitable for the application of a chuck wrench, the jaws being shown as gripping a pipe A.

At the left of the standard H is an electric motor 20, the shaft 2| of which is coupled with mechanism extending into the housing II and there connected by reduction gearing with a gear tight on the chuck barrel. The reduction gearing may be of any suitable type and is not fully shown but is indicated by the dotted lines 22 at Fig. 1. One form of such gearing is illustrated in my Patent 2,079,179, issued May 4, 1937.

In'Figs. 1- and 2, I have shown at 25 an arched frame extending over the motor and carrying an adjustable pipe support 28 for the projecting portion of the pipe in the chuck. The arched frame at its 'front carries the housing 3!] of the barrel switch. The controlling barrel in this switch has an upwardly extendin vertical shaft 3! from which an operating lever 32 extends horizontally toward the front'of the machine. This operating lever in the usual construction projects directly forward when in the off" position but may be swung either to the right or left to connect the motor for forward movement or for reverse rotation.

'So much of the construction as is 'above described is already in'use and is set out merely as showing a power drive or machine tool having a chuck controlled by a chuck Wrench and driven by an electric motor which is controlled by a switch having a horizontal operating lever.

Coming now'to my switchlock, suitable for the machine described, this look comprises a U- shaped member 40 extending around the switch barrel housing and pivotally connected at the ends of its arms to the frame of the machine be .hind the housing 30. This U-shaped member carries atits upper edge a .pair of spaced jaws 4 adapted to :stand on opposite sides of the switch lever 32 or to clear the same when the member 40 is lowered. This member carries also a pair of spaced jaws 42 extending forwardly from its lower portion and adapted to support a T-shaped chuck wrench, with its handle member resting on the jaws. Such wrench is shown at B in Figs. 4 and 6, and is indicated by broken lines in Fig. 2.

The locking member is preferably lightened by openings .3 of a general triangular shape in its two sides, giving it the upper portion 44, the diverging lower portion 45 and the connecting front portion 46 shown in the drawings. 1

I claim:

1. The combination of an electric switch having an enclosing housing and a switch lever projecting from the housing and swingable in a horizontal plane, a pivotally mounted U-shaped member extending about the switch housing and having means to coact with the switch lever, a spring tending to swing the U-shaped member upwardly The U-shaped frame 40 is given a tendency to, H

swing upwardly by a suitable spring, shown as a coiled spring 41, coiled about the pivotal axis of the member All and having one end, as 41a, exv tending downwardly and engaging the frame and the other end as 411), extending forwardly and then bent laterally beneath the upper portion 44 of the locking member. I

The pivoting of the locking member to the :frame is preferably effected by a through rod 49 extending through both arms of the member and through an intermediate portion of the frame member 25, this rod carrying suitable stops at its ends, as for instance cotter pins. A pro,- jecting end portion of this rod forms a convenient support for the spring coiled about it.

It will be seen from the description given that the U-shaped locking member of this invention may be readily mounted on existing machines having barrel switches, which are in common use. It is only .necessary to drill a hole through the frame for the passage of the pivot bolt 49 and then mount the locking member with its spring ing or unclamping, and the rem-oval of the chuck wrench from its support causes an automatic locking of the switch by reason of the rising of the locking member to embrace the switch lever, so that the switch is positively retained locked until the operator has completed the wrench operation and returns the chuck wrench to the forwardly projecting jaws of the locking member. These jaws form a very convenient support for the chuck wrench, and, even in the idle position of the device, provide a guard preventing the operator accidentally moving his body against the switch lever andunintentionally turning the motor on.

*It will be noticed that the outer edges of the switch locking jaws 4| are curved or inclined outwardly and downwardly with the result that if the operator after starting the machine with the chuck wrench on the locking device should thereafter remove the chuck Wrench while the machine is running, then when he swings the switch lever toward neutral position to stop the machine such action will cause the switch lever to engage one of the camming surfaces of the locking member and automatically depress that member as the switch lever comes into neutral position. Then the elevation of the locking member by its spring will immediately lock the switch lever'in neutral position and retain it locked until the chuck wrench is restored in supporting PQsition on the device.

on its pivot into such coacting position, said U- shaped member having also means for supporting a weight sufiicient to lower it into non-active position.

2. The combination of a barrel type of switch for controlling an electric circuit, said switch having an enclosing housing and a switch lever projecting above the top of the housing and 'swingable in a horizontal plane, a U-shaped member extending about the switch housing and having the rear ends of its arms pivotally mounted, said U-shaped member having a pair of shoulders adjacent its top adapted to coact with the .shaped locking member extending about the housing and having upwardly extending means adapted to engage the lever and hold it in neutral position, means for pivotally mounting the rear ends of the locking member, a spring between the machine frame and locking member tending to elevate it, and a pair of spaced jaws extending forwardly from the intermediate portion of the U -shaped member.

,4. The combination of a switch, a housing for the switch, the switch having a horizontally movable operating lever, of a U-shaped locking member extending about the switch housing and having its two arms pivoted to the frame at the rear of the housing, a springcoiled about the pivotal axis of the locking member and bearing at one end against said frame and at the other end against the locking member tending to elevate the locking member, the locking member having a pair of upwardly extending jaws adapted to stand on opposite sides of the switch lever when the latter is in idle position and the locking member elevated, and a pair of forwardly extending jaws adapted to carry a tool the' weight of which .will swing down the locking member against the action of its spring to release the switch lever. 5. The combination of a barrel switch having upright housing and an operating lever at the top thereof and movable-in a horizontal plane; a U -shaped lccking member extending aboutthe housing having its rear ends pivotally mounted, a spring tending to swing'the locking member upwardly, a pair of upwardly extending jaws carried by the locking member and adapted to embrace the switch lever when the latter is in oif" position and the locking member elevated, and a pair of spaced jaws extending forwardly from the intermediate portion of the U-shaped-locking member adapted to carry a tool the weight of which may lower the locking member against the action of its spring.

n 6. The combination ofa housing for a switch, the switch having a horizontally movable operating lever, of a U-shaped locking member extend-,- ing about the switch housing and having its two arms pivotally mounted at their ends, a spring coiled about the pivotal axis of the locking member and tending to elevate the locking member, the locking member having means to engage the switch lever when the latter is in idle position and the locking member elevated, and a pair of forwardly extending jaws on said locking member adapted to carry a tool the weight of which will swing down the locking member against the action of its spring to release the switch lever.

7. The combination of a switch having an upright housing and an operating lever movable in a horizontal plane adjacent the upper end of the housing, a U-shaped locking member extending about the housing having its intermediate portion beneath the operating lever, the rear ends of the member being pivotally mounted, said member flaring in an up and down direction toward its intermediate portion, a spring tending to swing the locking member on its pivot to move the intermediate portion upwardly, said intermediate portion being formed at its upper part with a pair of jaws adapted to embrace a switch lever when the latter is in its ofi position and the member elevated and with a pair of jaws extending forwardly from the lower part of its intermediate portion and adapted to support a tool the weight of which may lower the locking member against the action of the spring.

8. The combination of a switch having an enclosing housing and a switch lever projecting from the housing and swingable in a horizontal plane, a pivotally mounted U-shaped member extending about the switch housing and swingable in a vertical plane and having means to coact U-shaped member extending about the switch housing and having the rear ends of its arms pivotally mounted on a horizontal axis, said U- shaped member having a pair of shoulders adjacent its top adapted to embrace the switch lever and hold it in neutral position, a spring tending to swing the U-shaped member upwardly on its pivot, and a forward projection on the U- shaped member below the switch lever by which said member may be lowered.

10. The combination of a switch mounted in a vertical extending housing and having a horizontally movable operating lever, a U-shaped locking member extending about the housing, means for pivotally mounting the rear ends of the locking member, a spring tending to elevate it, and a pair of spaced jaws extending upwardly from the intermediate portion of the U-shaped member and adapted to straddle the switch lever and hold it in neutral position, the outer edges of said jaws being outwardly and downwardly inclined to form camming surfaces adapted to be engaged by the switch lever in moving toward off position.

11. In the combination of a switch having a vertically extending housing and having a horizontally movable operating lever, a U-shaped locking member extending about the housing, means for pivoting the rear ends of the locking member on a horizontal axis, said looking member having means to engage the switch lever when the member is elevated, a spring tending to elevate it, and means extending forwardly from the intermediate portion of the U-shaped member and adapted to support a sufficient weight to lower the member to idle position.

ROBERT B. PEALER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 728,590 Linn May 19, 1903 1,383,781 Ball July 5, 1931 1,829,263 Carlsen Oct. 27, 1931 1,910,217 Hadfield May 23, 1933 2,224,691 Pealer Dec. 10, 1940 2,246,919 Krantz June 24, 1941 2,444,188 Englund June 29, 1948 2,466,355 Baker Apr. 5, 1949 

